When considering the dwindling supply of fossil fuels and the extensive maintenance demands of the separate gas heating systems which we used to use, we chose in 2010 to build a wood-chip oven to supply all of our heating and hot-water needs. The electronic network of underground stations allows the energy to be used more effectively, providing heat only when and where it is needed. This, together with extensive efforts to better insulate the house, has helped reduce our energy requirements. In building projects we attempt to include 'gray' energy costs when choosing which materials and the necessary wood chips for our oven are supplied regionally.